![42h
ENTRYPOINT 2/2
• Run containers as executables! :)
$ cat /etc/passwd | docker run -i wc
• Dockerfile: https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/slide_10/Dockerfile
# This is wc
#
# VERSION 0.42
# use the base image provided by Docker
FROM base
MAINTAINER Roberto roberto@docker.com
# count lines with wc
ENTRYPOINT ["wc", "-l"]](https://image.slidesharecdn.com/dockerfilebasics-workshop-twitter-2013-11-05-131105154723-phpapp01/85/Dockerfile-Basics-Docker-workshop-2-at-twitter-2013-11-05-10-320.jpg)
Dockerfile Basics | Docker workshop #2 at twitter, 2013-11-05
- 1. @ Dockerfile Basics Docker workshop #2 at @Twitter, beginners class #dockerworkshop Docker version 0.6.5 By Julien Barbier @julienbarbier42
- 2. 42h Dockerfiles • Dockerfiles = image representations • Simple syntax for building images • Automate and script the images creation
- 3. 42h FROM • Sets the base image for subsequent instructions • Usage: FROM <image> • Example: FROM ubuntu • Needs to be the first instruction of every Dockerfile • TIP: find images with the command: docker search
- 4. 42h RUN • Executes any commands on the current image and commit the results • Usage: RUN <command> • Example: RUN apt-get install –y memcached FROM ubuntu RUN apt-get install -y memcached is equivalent to: $ docker run ubuntu apt-get install -y memcached $ docker commit XXX
- 5. 42h docker build Creates an image from a Dockerfile • From the current directory • From stdin • From GitHub $ docker build . $ docker build - < Dockerfile $ docker build github.com/creack/docker-firefox TIP: Use –t to tag your image
- 6. 42h Example: Memcached FROM ubuntu RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list RUN apt-get update RUN apt-get install -y memcached • Dockerfile: https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/slide_6/Dockerfile $ docker build –t memcached_d1 . • Test it $ docker run -i -t memcached_d1 /bin/bash root@1f452c9442fb:/# memcached -u daemon -vvv
- 7. 42h #Commenting • # • Dockerfile: https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/slide_7/Dockerfile # Memcached # # VERSION 1.0 # use the ubuntu base image provided by Docker FROM ubuntu # make sure the package repository is up to date RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list RUN apt-get update # install memcached RUN apt-get install -y memcached
- 8. 42h MAINTAINER • specify name / contact of the person maintaining the Dockerfile • Example: MAINTAINER Julien, [email protected] • Dockerfile: https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/slide_8/Dockerfile # Memcached # # VERSION 1.0 # use the ubuntu base image provided by Docker FROM ubuntu MAINTAINER Julien, [email protected] # make sure the package repository is up to date RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list RUN apt-get update # install memcached RUN apt-get install -y memcached
- 9. 42h ENTRYPOINT 1/2 • Triggers a command as soon as the container starts • Example: ENTRYPOINT echo “Whale You Be My Container?” • Dockerfile: https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/slide_9/Dockerfile # Whale you be my container? # # VERSION 0.42 # use the base image provided by Docker FROM base MAINTAINER Moby Dock [email protected] # say hello when the container is launched ENTRYPOINT echo "Whale you be my container"
- 10. 42h ENTRYPOINT 2/2 • Run containers as executables! :) $ cat /etc/passwd | docker run -i wc • Dockerfile: https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/slide_10/Dockerfile # This is wc # # VERSION 0.42 # use the base image provided by Docker FROM base MAINTAINER Roberto [email protected] # count lines with wc ENTRYPOINT ["wc", "-l"]
- 11. 42h USER • Sets the username to use when running the image • Example: USER daemon
- 12. 42h EXPOSE • Sets ports to be exposed to other containers when running the image (cf lightning talk by Michael Crosby @crosbymichael) • Example: EXPOSE 80
- 13. Exercice: create a perfect Memcached Dockerfile Answer https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/memcached/Dockerfile $ docker build -t memcached . $ docker run –p 11211 memcached #BOOM • Try it (update port number, $ docker ps) Python https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/memcached/test.py Ruby https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/memcached/test.rb PHP https://github.com/jbarbier/Dockerfile-Basics-Docker-Workshop-2-Twitter/blob/master/memcached/test.php 42h
- 14. 42h Quizz: Online Dockerfile Tutorials Test your skills here: http://www.docker.io/learn/dockerfile/